Radio system



March 9, 1937. PLEBANSKI RADIO SYSTEM Filed Sept. 8, 1934 2 Sheets-Sheet l .7 F5 lllllllllllll INVENTOR JOZEF PLEBANSKI %4/ flia ATTORNEY J. PLEBANSKI March 9, 1937.

RADIO SYSTEM Filed Sept 8, 1934 2 Sheets-Sheet 2 7 LOCAL OSULLATDR H pm m m A I AMPLIFIER MODULATOR VIIIl/l INETOR J'OZEF PLEBANSW BY ATTORNEY at... Mar. a, 193':

UN TED m 4 ao'lzsaan'apro srs'rnu; Jozef Plebanski, Warsaw, Poland, assignor to Radio Patents Corporation, New York,.N. Y a

corporation of New York Application September a, 1934, Serial No. 143,253 I In Poland mm 3, 19s: r

i is (Cl. 250-11) times extending over several miles of territory 15 especially for longer wave lengths. resulting high initial and installation costs. It is an object of my invention to provide a novel system for directive transmission and/or reception of wirelesssignals by which a desired sharp- 20 ness or directive characteristic may be obtained in a simple and easy manner with only little or practically no spacing being required between the aerial systems used.

Another object of the invention consists in the 25 provision a single of a directive aerial system requiring the directive transmitting and/or receiving beam 30 in a desired direction may be secured in an easy and simple manner.

Another disadvantage of directive antenna systems especially those for longer wave lengths involving large extended 35 aerial arrangements is the fact that it is diiflcult 'or impossible to-change the transmitting and/or receiving direction of the wireless beam to suit varying. conditions ofoperation.

Accordingly it is a further object of my inven- ,40 tion to provide a novel directive transmitting vand/or receiving-system and method for operating the same whereby the transmitting and/ or receiv- -ing direction may be varied readily and easily and g without the expenditureflof excessive apparatus. 45 Another-object of the invention is the proviaim of a directive antennaarrangement for transmitting. and/or receiving wireless signals in which the angle of the directive transmitting and/orreceiving beam may be varied at will in'an easy e 'and simple manner, thus making it possible forinstance to use a wide angle for simultaneous communication with a number of stations and alternatively with a narrow concentrated beam ter communication between single stations, thus v515 eliminating interference and yof ' receivin directive antenna with aplurality of associated goniometer arrangements in .such a manner that any desired degree of sharpness of the known typeof the communication and increased transmission emcieney. I

Still a further object of the invention is to provide a-n'ovel directive transmitting and/or receiving aerial system for wireless communication especially adapted for communication by means of 011" and 0113" signals such'as in the case oftelegraphic code transmission, picture transmission, etc., in which disturbances such as signals a from an interfering statiomatmospherlc disturbances, etc. do not affect the'spacing characteristicsbetween the signals but merely increase the intensity of. the signals in such a manner as to strengthen the signals and, under given circumstances, to improve the volume of reception.

I with the above and further objects in view, the invention generally involves the provision of .a plurality -of differently oriented directive aerial systems all operating atI-the same signal frequency, and means and methods for combining the signals received by the individual antenna into a common signal. In a preferred form the indi-; vidual antennae are oriented in such a manner that the peri -receiving sectors or anglesof the respective polar radiating diagrams are adjoining one another in such a manner as to decrease the resultant receiving angle or sector ofthe combined antenna system. In an arrangement of this type, as will be described in more detail here- 7 after, it is seen that a disturbing si n whose direction comes within the non-receiving sector of one antenna and within the receiving sector of another antenna will not destroy the spacing characteristics betweenathe signal impulses 7 especially telegraphic signals or the like, but will .merely increase the signal amplitude whichmay be either compensated, such as by the use of limiting devices, or may be usefully employed to increase the signal strength; As is understood.

the invention is applicable to the elimination of 40 both interfering signals of distant stations and to static or other atmospheric or man-made disturbances picked up by the receiving antenna. As is well known, atmospheric disturbances I such as static usually arrive in a preferred direction whereby. suppression of such interference is possible by the use-of directive antenna systems. However, if both the receiving sisnalsand the disturbance, such as an atmospheric disturban arrive in the same direction, nosuppression is possible as is obvious. But the latter condition is likely. to occur only rarely. Therefore practically theme of directive systems has been found. to be the most eifeotive-means for eliminating interference preferably of the random character,

g 2 such as atmospheric disturbances or similar manmade interference originated from power lines,

Figure 9 illustrates the effect of eliminating interference of telegraphic or similar signals by using a transmitting and/or receiving antenna arrangement of the invention.

Figure 10 shows a general form of receiver in a schematic manner according to the invention.

Figure 11 illustrates a simplification of the receiving organization used in accordance with the invention.

Figure 12 illustrates a preferred type of single directive antenna to be used by the invention in combination with a multiple type goniometer arrangement; and

Figures 13 and 14 illustrate signal forms especially useful in transmission and/or receiving systems and methods according to the invention.

Referring to Figures 1 and 2 of the drawings, I have shown the receiving characteristicski and k2 in the known polar diagram form of two directional aerials such as receiving aerials and having a known cardioid shape with their axis (A0 and 3-0, respectively) oriented as shown to include approximately a right angle. The direction of the desired signals to be received is indicated in both figures by the arrow I-O. From the diagrams it is seen that the antenna of Figure 1 schematically shown at A, is non-receptive over an angle or sector of approximately as indicated by the cross-hatched area at E while the antenna indicated at B (Fig. 2) has a similar non-receiving sector covering an angle of 90 in a difierent direction as shown by the cross-hatched portion F.

As 'is well known, antennae of this type having a cardioid shaped polar transmitting or receiving diagram are well known in the art and for this reason are not shown in detail in the drawings for the sake of simplicity and ease of illust'ration. Thus for instance, a cardioid shaped polar diagram is obtained by-an ordinary loop antenna combined with an open antenna with the loop properly oriented and having its plane coinciding with the desired axis of the cardioid or by a plurality of separately spaced antennae arranged at a proper distance from each other, and/or with the phase of the radiated or receiving waves of the individual antennae properly adjusted,'as is well known.

Referring now to Figure 8 of the drawings illustrating schematically a receiving system to be used in combination with a plurality of antennae having receiving diagrams as shown by Figures 1 and 2, it is assumed that the first antenna A (Fig. 1 is-connected to a receiver of standard type and construction and that the received wave is changed from the received frequency to an intermediate frequency I1A1 for example being equal to 90 kilocycles such as by a well known frequency changing system such as by means of a local heterodyne or beating oscillator indicated at H1. Receiving systems of this nature are well known as super-heterodyne receivers comprising a mixer or frequency changing stage and for this reason have been indicated only schematically as being unnecessary to the understanding of the invention and in order to simplify the illustration in the drawings. It is further assumed that the second antenna B as shown by Figure 2 is similarly connected to a second receiver and that the same receiving signal is changed to another intermediate frequency I1A2 such as by means of a second heterodyne or mixer oscillator shown at Hz, this second intermediate frequency being for example equal to kilocycles. -As is well known, an incoming frequency may be easily changed into any desired frequency by combination with a local frequency (heterodyne oscillator H1H2 etc. in a frequency changing or mixer device such as a mixer tube, the combination frequency being equal to the sum or difference of the mixing frequencies. I

The output frequencies from both intermediate frequency stages are then combined in turn in a similar manner to yield asecond intermediate frequency I2A12 which in the example given will be 130-90 equal to 40 kilocycles. It is seen that if a disturbing signal arrives in a direction coming within either cross-hatched or non-receiving spectively, no intermediate frequency signal shall be produced in I2A12 in both cases since no signal will be received either in the first or in the second case, as is obvious, and accordingly no beating signal will be present in the mixers or frequency changers IlAl and I1A2, respectively.

In the latter case the intermediate frequency amplifier IzA1z shall behave as if the directional characteristic of the entire system combining the aerials according to Figures 1 and 2 would have a shape K- as shown by Fig. 3 from which it is seen that the non-receiving angle has been increased from 90 to (shown by the crosshatched areaL in Fig. 3) with both non-receiving sector areas L and F adjoining and adding each other.

areas E or F according to Figures 1 and 2, re-

will therefore be eliminated by the antenna A (Fig. l) but will be received by'the antenna B (Fig. 2). If in the latter the desired signal is absent, suchas during the spacing intervals as in the case of telegraphic code or similar signals, the disturbing signal will be eliminated since there is no second signal present to combine with V in the frequency changer orsecond intermediate stage I2A12. If the desired signal appears, that is, during the on periods of telegraphic code or similar signals, the disturbing signal will also appear in the output of the receiver added to the signal amplitude but without efiecting or destroying the characteristic of the spacing intervals between the signalling impulses. 4

This is seen more clearlyfrom Fig. 9. In this figure, I illustrates the desired receiving signal such as a telegraphic code signal as shown,'II represents a similar disturbing signal arriving from an interfering station. Since the interthejcharacteristic shown periods and accordingly also the-lengths of the signal impulses which in the case ofcode or sim-- ilar transmission determines'the character of the e signals being transmitted, are not destroyed but only the signal amplitudes are strengthened since only during the signalling periods a disturbins signal'is beating with the desired signalin the heterodyne or frequency changing stage, as .explained before.

The latter effect can however be used to-advantage because it increases the desired signal strength as is readily seen and if the output of the receiver is connected to a suitable translating device, for instance such as a sound receiver or a-direct current bridge arrangement supplying a recording instrument of, any. kind,'the strengthening efl'ect of the disturbing signal as stated. can be useful and advantageous. On the record ing tape of the receiver or in the tone reproducer output, the disturbance would not be present due to the usual use of operating or limiting devices employed with such arrangements. The, output signals shall therefore-have a-shape as shown in IV, Figure 9; that is, equal to the desired receiving signal, the eifect of the interfering signal having been practically eliminated. The same consideration applies to other disturbing signals of a more random character-such as atmospheric the shaded areas E and F according to Figures 1 and 2. Such disturbances shall also be de-' tected only in the output as long as the desired signal is received; that is during the spacing in- 40 tervals between the signal current impulses. as

is readily understood from the above.

- The directive effect and'interference elimina- I tion by means of arrangements of the WW as described can be further increased byproviding an increased number of individual antennae with properly oriented directivecharacteristics' such as for instance by combiningfour antennae having cardioid receiving diagrams in, .ka, 16:, k4

oriented, as shown by Figures 1, 2, 3 and 4, in

. which case the over-all-dire'ctional characteristic K will have a shape as shown in Figure 6 as compared to a characteristic for two antennae shownby Figure 3-. -It is seen that a characteristic of this type gives substantially equal reception over a deflniteangle a due to the square top shape of order to secure sucha characteristic- -comprising four or more antennae, it isnecessary, as shown in Fig. 8, to provide four frequency changer or heterodyning stages for eachantenna IiAi, 11M, IiAs, I AA, in vided with an .individuallocal oscillator H1. Ha H3, H4. respectively, and each beatingdown the incoming signal. to a different first intermediate frequency 'such as to. 90, 130, 1'16, and 200 kilocycles respectively, as shown in the example; The first two intermediate signals (;and 180 kilocyciesl are then combined in turn, as de-' scribed above, yielding a second intermediate frequency as in the example equal to 40 kilocycles while the signals of D in'the example shown are combined similarly to produce a second intermediate frequency. 12mm the example shown equal to 200- equal .7 to 25 kilocycles. Then both the second interme-' disturbances arriving in directions coming within in the drawinsa ,In,

the example shown pro-f the antennae C and diatefrequency (mm and 12AM) arecombined in their turn in a similar manner to yield a third and final output frequency IsAim in the example equal to ill-25:15 kilocycles which isthe final.- receiving frequency and which serves to operate -.a suitable translating device (printer,.sound receiver) after further amplification and/or detection as is well known in radio receiving systems.

As will be seen, an arrangement of the type according to the invention'is easily adapted for varying the directional characteristics by-varying thecharacteristic of either one or more of'the individual antennae units. Thus, for instance, if

the directional characteristic k: of the antenna 0 as-shown by Fig. 4 is rotated in a clockwise direction and the characteristic k4 of the antenna D shown by Fig. 5 is rotated in an anticlockwise direction as indicated by .the. arrows in the respective diagrams, the over-all radiating characteristic of the four aerials A," B, C. D (Figures 1 to 4) may be narrowedinto a very sharp beam and a characteristic K" obtained-as shown by Fig. '1.

The same characteristic may be secured, .as is understood, by combining two systems each comprising four aerials and each havinga characteristic as shownby Fig. 6. In this case the systems mustbe displaced so as to leave an angle as desired. say about 10 corresponding to the desired receiving angle as shown by Figure 7;

From the above it is seen that the invention provides easy and simple means for varying the angle or concentration of the transmitting and/or receiving beam to suit various purposes, such'as 'for simultaneous communication to and/or from .aplurality of stations coming within the larger sector area of the directive characteristic, or alternatively for communication to and/or from a single station,'in which case a very concentrated beam or narrow sector of the directive characteristic may be adjusted.

As is further seen, directive arrangements of the type described are easily adapted for changing the transmitting and/or receiving direction or the opening angle of the directive beam either by turning the loop aerials, if such are used as individual antennae. or if spaced fixed antennae are i used,- by means of associatedgoniometer devices well.known to those skilled in the art. Due to the reduced dimensions and extension of direc- .tive systems of the type according to the 'invention, the transmitting and/or receiving direction thus easily be varied without involving .the

my diiiic'ulties of extended directive antennae heretofore known inthe art using spaced an-- tennae and covering extended areas.

As is understood, the system of the invention is not limited to fouror eight-serials as de-I' scribed. As many'aerials may be used as desired ,to increase the sharpness or degree of concern .tration of the directive beam and it is furthermore understood that the directive diagram of the individual'aerials may have any desired shape differing from the cardioiddiagramsshownforthe of illustration. It is only essential for the invention that each directive aerial .used haves.-

receiving angle. or angles andanother angle over which the aerial is non-receptive to incoming -8, shows schematically a general receiving ar-' signals. Figure 10, otherwise being similar to Fig. f

of the receivers each to be connected to one of a corresponding number ofdifferently orienteddirective serials are' shownat A, B] z. The

received input signals are then changed each to a different first intermediate frequency as by means of frequency changers or mixer stages shown at a1, a2 (Zn-l. The thus obtained first 5 intermediate frequencies are then combined in groups of two to secure the second intermediate frequencies in the stages as shown at b1, b2 bn/2. The thus obtained second intermediate frequencies are then in their turn combined in groups of two to yield third intermediate frequencies c1, c2 Cn/4 which in a similar-manner will be combined to secure the fourth intermediate frequencies (11, d2 until a single final output frequency e, as shown in the drawings, is obtained. Instead of using many successive intermediate frequency amplifiers as shown, only one second intermediate amplifier may be used in which n first intermediates are combined. In this case, however, the output of the second intermediate amplifier IiAi2 u (see Fig. 11) must be very selective and chosen so as to be operative only for a combination of all n first intermediates; in other words, it must be inoperative if one of the first intermediates fail. Thus for instance, the separate intermediate frequencies produced by the frequency changers a1, a2 an in a system as shown by Fig. 11 may be applied to a common mixing circuit such as the grid circuit of a mixer tube with a sharply tuned circuit connected in its anode circuit corresponding to the desired final output frequency. In this manner one intermediate frequency will beat with another to yield a first difference frequency which in turn may beat with another intermediate frequency yielding a second diiferencefrequency, and so. forth until a frequency is obtained corresponding to the desired output frequency to which the anode circuit is sharply selective whereby all other frequencies will be filtered out and suppressed. It is seen that if one of the receiving signals fail, no output signal will be produced or the spacing intervals between the signals will not be effected if a disturbing signal falls at least within one of the non-receiving angles of the individual directive antenna units, as explained herebefore. In case of many first intermediates this is diflicult' to obtain and therefore it is advisable to use a combination as shown in Fig. 10. The output frequency in any case must be determined by the previous intermediate-frequencies in such a manner that if one frequency fails the output is non-responsive.

Since the system according to the invention as described is independent of the spacing of the aerials although for mechanical reasons the aerials may be spaced if desired, a single aerial may be used for instance in accordance with a further feature of the invention, in the form of a Bellini-Tosi double frame aerial associated with a corresponding number (generally n) of gumometer devices to secure the differently oriented directive characteristics, each goniometer being associated with a separate receiver unit and combined with a vertical antenna if desired. Asis well known, goniometer devices as of theBellini- Tosi type usuallycomprise a fixed flux carrying member such as an inductance coil connected and definitely oriented in relation to a directive antenna, and a movable fiux carrying member such as a movable coil associated therewith whereby the output signal in the movable coil is dependent on its orientation and definitely related to the direction of the incoming signals. In this case a most simplified transmitting and/or receiving arrange- 75 ment is obtained requiring only a single aerial According to a preferred embodiment of the invention, a directive antenna system of the known Marconi-Adcock type with associated goniometer arrangements is used, such as illustrated in Fig. 12 in which case only a single pair of aerials A and A" are required. The movable goniometer coils are shown schematically 'at i1, i2 in. ,The movable goniometer coils may be mounted on a commonshaft or otherwise coupled mechanically for'unitary operation by means of an'operating handle as indicated at h. In order to ascertain the relative correct position of 'movable goniometer coils in respect to the fixed goniometer coils L1, L2 Ln, the latter may be arranged as to be rotated and shifted in respect to the. movable goniometer coils. Using such movable goniometers the operation will be such that the desired signal is tuned on the goniometer equal within 1 to 30 of maximum loudness in accordance with the desired directional characteristic of the system. While in the example shown the goniometers are connected in series with the antennae A and A", they may be connected in any other suitable manner in accordance with the spirit of the invention.

As is understood, it is also possible to associate with the same aerial system a large numberbe substantially free from interference arriving.

from all directions excepting the direction ofthe desired receiving signal. The greater the intensity of the'disturbance, such as static and atmospheric disturbances, the greater the increase of the signal volume. Thus the system according to the invention is both highly directive and at the same time acts as an interference eliminator.

The sharpness of the directional characteristics and the gain in signal to noise level ratio depends to a large extent on the sharpness or definition of the blank receiving angles of the individual antenna units. If it is assumed that the interfering signals or noises arrive. simultaneously from all directions and are exactly in synchronism, then the system as disclosed, like any other directive system would give no improvement since the beats between the disturbances would be present in all the intermediate amplifiers (Fig.v 8). However, it is well known that disturbances such as static or othershock-like interference of short duration and with random character arrive in most cases from a preferred direction although somewhat indefinite and variable. Thus under practical circumstances the novel systems as described while perhaps not securing the characteristic effects to as higha degree asin the case of'the more complicated and extended directive systems known in the arriving in sequence each from the same or from various directions but not over-lapping each other, then the character'of such disturbances may be even useful to the system by increasing the gain and inturn the signal to noise ratio in they receiver. If some of the disturbances overlap each other 'and .if the over-lapping signals fall within the non-receiving angle of any one of the unit antennae, such a disturbance will also be'eliminated. -If the over-lapping disturbances come from opposite directions which, however,

is not very likely to occur except in rare cases,

theover-lapping periods may create interference coming within the spacing periods of the transmitting signals. The same applies to more than one disturbing telegraph signal coming for instance both from opposite directions. It is therefore reasonable to assume that the general gain in signal and noise ratio shall be less than exhibited-by the directional character but of course substantially higher than the gain for each single unit alone.

The systems described above according to the invention are primarily adapted for reception of 2s telegraphslgnals where the carrier is interrupted '(ICWtransmission) and are suited for both long and short waves. However; the invention.

- may also. be applied to the transmissionand/o'r e eption of telephone or similar transmission,

3 that is, continuous modulation of the carrierwave without the use of current limiting devices -.in the output stages. Since intransmission of this nature the carrier is always present, the

disturbance is not eliminated but the-system is lso well'sulted, for taking bearings indirection finding with modulated telephone signals.

If it is desired to receive modulated carrier waves with elimination of atmospheric and other disturbances in the manner as described above, a 40 special modulation-must be used for the transmission. Thus by using a carrier wave of constant intensity and interrupted periodically according to the modulating frequency such as shown in Fig. .13 (constant amplitude, variable 46 signal length) or as shown in Fig. 8 (constant amplitude and constantsignal length but varying frequency) the systems under the invention are suited for reception of modulated carrierwaves such as telephonyor the like with elimination of 50 atmospherics and other disturbances as is readily understood Atom the above. Thus the invention is particul transmission in which, on account of atmospheric and other disturbances and dlfliculties, it is customary to translate the picture signals varying gradually in accordance with varying degrees of light and shade ofsuccessive elementary areas of a picture. or image to be transmitted, into impulses of substantially equal amplitude but veryi i0 ing duration in\ accordance with the amplitudes of the original modulating or picture impulses such as shown by Figure 13. 2

whilethe invention has been described inconnection with the receivingsystem, it is understood that'it equally applies to transmitting arrangements. Thus for instance,.by using four directional transmitting aerials radiating accordingto characteristics as shown by Figs. 1 to 4 and assuming that by each unit antenna a separate wave length is transmitted, such as for examplep90, 130, 175, 200 kilocycles, respectively, as chosen'in the example and further assuming that the receiver is provided with fournon-directive 'aerials A, B, C, D associated with a receiver 76 of the type as show by Fig. 2 which may be either y adapted for usein wireless picture.

of. the straight high frequencytype or a receiver operated on the super-heterodyneprinciple and tuned to the respective frequencies 90, 1'30, 1'75, I 200 kilocycles respectively, it is seen that in this case the whole receiving system shall receive the aovaeea '4 5' composite four wave transmission lithe receiver is located in the direction of the maximum radiation of the transmitting characteristics which in this case will have a shape similar as shownin Figures 6 and '7. l

Systems of the type according to the invention,

'in particular due to the ease andsimplicity of adjustment and relation of-the directional characteristics, as pointed outhereinbefore, are well suited for use as radio beacons and it is understood that when used as a transmitter a single antenna may beprovided with a. plurality of associated Bellini-Tosi goniometers similar .as described above in connection with the receiver.

The systems of Figures 8, 9, and mare-also suitable for diversity reception and not only for telegraphy but also for telephone worlrimodu-v lated carrier). In fthiscase the antennae -A, B, i

C Z (directional or not) must be suitably spaced. The diversity reception is possible because all intermediate. frequencies are not dependent from the relative phases'in the various .antennaej It can be shown that an intermediate frequency produced by the beats of two'modulated carriers shall increase the percentage-of modulation and gives distortion (secondv harmonicof the speech frequency). Thisdistortion can be avoided if the modulation of the. received signal is low, or if in the receiving systemsof Figures 8, 9, 10 the carrier is increased artificially, or if in one or some amplifiers only the lcarrieris V allowed to pass-and the modulation. suppressed. In any case, the carrier and ,themodulation in such diversity system tendftobe constant and tend to compensate the fading (not simultaneously occurring in all antennae) While the invention has been described with specific reference to the accompanying drawings,

it is not to be limited, save as defined-in the appended claims. V

Iclaim; I

1. A directive radio system comprising a pinrality of diiferentlyoriented directive aerials each adapted for receiving a common signalling frequency wave; means for changing the individual secondary currents of different predetermined characteristics; means for combining s'aidsecondary currents and deriving a single resul ant, output current having a predetermined sel I and means for selectively translating saidoutput current.

3. A directive radio system comprising a plurality of diflerently oriented directive aerials each adapted for receiving a. common 1 8 signalling currents received by said aerials into ive characteristic which is a product function of the frequency wave: frequency changing means connected to said aerials to change the separate signalling currents received by said'aerials to intermediate currents of different frequencies; 5 means for combining said intermediate currents to secure a single composite output current having a predetermined frequency. which is aproduct function of all the frequencies of said intermediate frequency currents; and means for sel lectively receiving said output current.

4. A directive radio system comprising a plurality of diiferently oriented directive aerials each adapted to receive a common radio signal; frequency changing means for changing the signals 1 received by said aerials into intermediate signals each having a different frequency; means for combining said intermediate frequency signals in groups of two to secure secondary intermediate frequency signals; means for further successively combining said'secondary intermediate frequency signals; and means for similarly successively combining the resultant signals to derive a single resultant output signal of predetermined frequency. 7

5. A directive radio system comprising a plurality of differently oriented directive aerials each having a cardioid shaped directive characteristic and adapted to receive a common radio signal; a plurality of frequency changing means for changing the signals received by said aerials to intermediate signals each having a different frequency; further frequency changing means for deriving second intermediate frequency signals by combination of said first intermediate frequency signals; and means for combining the resultant signals in succession until obtaining a single resultant output signal of predetermined frequency.

6. A directive radio system comprising a plu- 40 rality of directive aerials each having a cardioid shaped directionalcharacteristic, said aerials being oriented in such a manner that the non-receptive sectors of their characteristics adjoin each other; means for simultaneously receiving 4 a common signal frequency wave by all said aerials; means for differently modifying a characteristic of the current received by said aerials and for deriving a resultant current from all the modified currents which has a predetermined selective characteristic determined by the characteristics of each of said receiving currents; and means for selectively translatingsaid resultant current.

7. A directive radio system comprising a" plurality of directive aerials each having a cardioid shaped polar directional characteristic, said aerials being oriented so that the receptive angles of their directional characteristics variably overlap each other; means for simultaneously and separately receiving signals by all said aerials from a single source of radiation; means for differently modifying a characteristic of thesignals received by said aerials and for combining the modified signals and deriving therefrom a resultant output current with a predetermined selective characteristic which is determined by the characteristics of each of said modified currents and means for selectively translating said output current to secure a receiving angle of desired angular spread of the resultant directional characteristic of all said aerials combined plotted with respect to said output current.

8. The method of radio communication by utilization of a plurality of receiving systems hav- 7 ing different directional characteristics which consists in diflerently modifying a characteristic of the separately received currents and combining the modified ciu'rents to derive a resultant current having a selective charactermtic which is a function of the characteristics of each of the received currents; and selectively translating said resultant current.

9. A directive radio system comprising a plurality of directional aerials adapted to receive.

signals from a single source of radiation; means for modifying the signalling currents received by said aerials to have predetermined different characteristics and combining the modified currents into a single composite output current of a predetermined frequency determined by the characteristics of each of said modified currents means for selectively transplanting said output current; and means for differently orienting said aerials to obtain a desired all-over characteristic by a variable overlap of the individual directional characteristics of said'aerials thereby securing a desired angular spread of the resultant directional receiving characteristic of all said aerials plotted with respect to said output current.

10. Adirective radio receivin y tem comprise ing a directive antenna; a plurality of goniometer devices having primary and secondary coils, said primary coils being connected to said antenna and being diflerently oriented relative to each other; means for combining the output currents in said secondary coils of said goniometer devices obtained from a common signalling frequency wave received by said antenna to derive a single resultant output current having a predetermined frequency which is a function of all said signalling currents and means for selectively translating said output current.

11. A radio receiving system comprising a directive. receiving antenna; a plurality of goniometer devices each having primary and secondary coils; said primary coils being connected to said antenna for receiving a common signalling frequency wave; means for superimposing the receiving currents in the secondaries of said goniometers to derive a single composite output current of predetermined frequency; means for selectively translating said output current; and

means whereby said goniometers produce a cardioid shaped directive characteristic, the primary coils of said goniometers being oriented in such a manner as to secure a resultant all-over directional characteristic of desired shape plotted with' respect to said output current.

12. The method of receiving radio signals by utilization of a plurality of receiving antennae having different directional characteristic'sconsisting in changing the received signalling current components to secondary currents of difierentfrequencies, combining said secondary currents into a composite output current having a frequency which is a function of all the frequencies of said secondary currents, and selectively translating said output current.

13. The method of receiving radio signals by utilization of a plurality of receiving antennae having different directional characteristics consisting in modifying the received signal currents to have different predetermined characteristics, combining said modified currents into a resultant current of a predetermined selective characteristic which is a function of all of the characteristics of the modified currents, and selectively V sistlng in heterodyning eachot the separately received signalling currents with-locally produced oscillations to derive therefroma plurality of secondary receiving currents of separate predetermined frequencies, and mutually heterodyning said secondary currents to derive therefrom a single resultant current having a Irequencywhich is determined by each secondary currents, and selectively translating and receiving said resultant current. f 15. The method of radio communication consisting in receiving a plurality of separate electric currents from a single source or electromagnetic waves each of which has a different predetermined relation with the direction ct the said electromagnetic waves; diflerently modifying a of the frequencies of said .each of which has a characteristic of the separately received currents and combining the modified currents to generate sists in receiving a plurality of separate electric currents from a source of electromagnetic waves diflerentfixed relation with the direction of said waves; changing the separately received currents into secondary currents of diflerent frequencies and combining the secondary currents into a resultant current of predetermined frequency determined by the frequencies of all the secondary currents; and se-- lectively receiving said'resultant current.

' JOZEF PLEBANSKI. 

